An understanding of the cortical representation of acoustic space has remained elusive despite evidence that AI is necessary to localize acoustic stimuli, and a number of careful studies have addressed this issue. These experiments will study the psychophysical ability of macaque monkeys to localize acoustic stimuli and simultaneously record the responses of single neurons in the primary auditory cortex (AI). The long-term aims are to determine the neural correlates of sound localization ability in the cerebral cortex and to define the cortical representation of acoustic space. One monkey is currently being trained to make saccadic eye movements to acoustic targets presented in complete darkness for a fluid reward. The stimuli are presented at different locations in azimuth and elevation throughout the central region of acoustic space while the responses of single neurons in AI are recorded. The effect of bandwidth and spatial location on neuronal responses will be determined for both single neurons and the population of neurons recorded across AI. These responses will be compared directly to the monkeyUs ability to localize the same acoustic stimuli. Sound localization in rhesus monkeys is a good model system to study stimulus feature representations in the cerebral cortex, as humans and macaque monkeys have similar sound localization abilities and show similar perceptual deficits following a variety of cortical lesions. A better understanding of the cortical mechanisms of perception has implications for rehabilitation therapies and treatments of neurological disease, injury and stroke. The experiments proposed here will combine psychophysical and neurophysiological techniques to determine the behavioral abilities and neural correlates of localizing stationary acoustic targets. *KEY*Macaque, Auditory cortex, Sound localization, Electrophysiology